Assessments - 3, GPA: 3.7 ( )

Fabricante : Campbell Hausfeld Arquivo Tamanho: 2.29 mb Arquivo Nome : Língua de Ensino:

EVERY 3 MONTHS: 1. Replace any unreadable safety labels on the welder. 2. Use compressed air to blow all dust and lint from ventilation openings. 3. Clean wire groove on drive roller. Remove drive roller and use a small wire brush to clean. Replace if worn or damaged. Supply Cable Replacement 1. Verify that welder is OFF and power cord disconnected. 2. Remove welder side panel to expose switches. 3. Disconnect the power cord leads per the diagram inside the unit. 4. Disconnect the ground wire connected to welder base. 5. Loosen the cord strain relief screws and pull cord out of strain relief. 6. Install new cord in reverse order per the diagram inside the unit. 7 Wire Feed Arc Welder Welding Guidelines General This welding machine can utilize the Flux Cored Arc Welding (FCAW) process or the Gas Metal Arc Welding (GMAW) process. The weld must be protected (shielded) from contaminants in the air while it is molten. The FCAW process uses a tubular wire with a flux material inside. The flux creates a shielding gas when melted. The GMAW process uses inert gas to shield the weld while molten. When current is produced by a transformer (welding machine) and flows through the circuit to the weld wire, an arc is formed between the end of the weld wire and the work piece. This arc melts the wire and the work piece. The melted metal of the weld wire flows into the molten crater and forms a bond with the work piece as shown (Figure 7). Slag Weld Wire Flux (Gasless only) Work Piece Shielding Gas Contact Tip Crater Nozzle Figure 7 - Weld Components Arc Welding Basics Six basic techniques affect weld quality. These are: wire selection, heat setting, weld angle, wire speed, travel speed, and electrode extension. An understanding of these techniques is necessary for effective welds. HEAT SETTING The correct heat involves the adjustment of the welding machine to the required setting. Heat or voltage is regulated by a switch on the welder. The heat setting used depends on the size (diameter) and type of wire, position of the weld, and the thickness of the work piece. Consult specifications listed on the welder. It is suggested that the welder practice with scrap metal to adjust settings, and compare welds with Figure 9. WIRE TYPE AND SIZE The correct choice of wire type involves a variety of factors, such as welding position, work piece material type, thickness, and condition of surface to be welded. The American Welding Society, AWS, has set up certain requirements for each type of wire. FLUX-CORED WIRE E -70T -GS Weld strength, times 10,000 pounds per square inch Welding positions (0 for flat or horizontal, 1 for any position) Tubular flux-cored wire Flux type AWS E71T-GS or E71T-11 is recommended for this welder. SOLID WIRE ER -70 S -6 Weld strength, times 1,000 PSI Solid wire Wire composition ER-70S6 is recommended for this welder. WELD ANGLE Weld angle is the angle at which the nozzle is held during the welding process. Using the correct angle ensures proper penetration and bead formation. As different welding positions and weld joints become necessary, nozzle angle becomes an increasingly important factor in obtaining a satisfactory weld. Weld angle involves two positions travel angle and work angle. Travel angle is the angle in the line of welding and may vary from 5. to 45. from the vertical, depending on welding conditions. Work angle is the angle from horizontal, measured at right angles to the line of welding. For most applications, a 45. travel angle and 45. work angle is sufficient. For specific applications, consult an arc welding handbook. 5. - 45. WORK ANGLE 5. - 45. TRAVEL ANGLE Figure 8 - Weld Angle WIRE SPEED The wire speed is controlled by the knob on the front panel. The speed needs to be “tuned” to the rate at which the wire is being melted in the arc. Tuning is one of the most critical functions of wire feed welding. Tuning should be performed on a scrap piece of metal the same type and thickness as that to be welded. Begin welding with one hand “dragging” the torch nozzle across the scrap piece while adjusting the wire speed with the other hand. Too slow of speed will cause sputtering and the wire will burn up into the contact tip. Too fast a speed will also cause a sputtering sound and the wire will push into the plate before melting. A smooth buzzing sound indicates the wire speed is properly tuned. Repeat the tuning procedure each time there is a change in heat setting, wire diameter or type, or work piece material type or thickness. For Aluminum, wire speed is typically set higher (7-9 speed range). TRAVEL SPEED The travel speed is the rate at which the torch is moved across the weld area. Factors such as diameter and type of weld wire, amperage, position, and work piece material thickness all affect the speed of travel necessary for completing a good weld (See Figure 9). When the speed is too fast, the bead is narrow and bead ripples are pointed as shown. When the speed is too slow,...

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